Gain calculating device

Abstract

A more preferable WB gain is calculated during strobe illuminated photography. When a WB gain for an image captured through strobe illuminated photography is calculated, the degree of contribution of strobe light is first estimated. When the degree of contribution is estimated, the image is first divided into a plurality of blocks, and typical brightness values and typical color values of the respective blocks are determined (S23). Subsequently, the highest-brightness block among the blocks analogous to the color of strobe light is identified as a strobe color block (S26). When there is a strobe color block, the degree of contribution of strobe light is estimated on the basis of the position of the strobe color block, a difference between the brightness of the strobe color block and the brightnesses of other blocks, and the like (S32 to S48). Meanwhile, when there is no strobe color block, the degree of contribution is estimated on the basis of the position of the highest-brightness block having the highest typical brightness value among the plurality of blocks (S28, S30).

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to Japanese Patent Application No. 2006-831 filed on Jan. 5, 2006, which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a gain calculating device for calculating a white balance gain suitable for at least an image captured through strobe illuminated photography.[0004]2. Related Art[0005]In the field of cameras, there has been widely known a white balance technique for correcting the color of a captured image according to the type of a light source employed at the time of capture of the image, and the like. This technique is an image processing technique for eliminating a discrepancy between an impression which a photographer had during photographing action and an impression given by an output image, which is caused by the color of the light source employed during photography.[0006]A technique for taking in...

AI Technical Summary

Benefits of technology

[0026]According to the present invention, the degree of contribution of strobe light is assumed on the basis of an actually-captured image, and hence a highly-reliable degree of contribution of strobe light is obtained. Consequently, a more preferable white balance gain can be obtained.

Problems solved by technology

Therefore, when strobe light has not sufficiently reached the subject or when strobe light has been radiated with excessive intensity on the subject, there arises a problem of a failure to compute an appropriate white balance gain.

However, any of these conventional techniques involves estimating the degree of contribution of strobe light from information extracted from factors other than a captured image such as a distance to a subject and information about flash light.

Therefore, the conventional techniques cannot be said to have a high degree of precision in estimating the degree of contribution of strobe light.

The low degree of precision in estimating the degree of contribution of strobe light poses difficulty in performing white balance processing suitable for strobe illuminated photography.

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